Patent GB-839963-A (GB)
Title: Improvements in or relating to machines adapted for use in assembling electrical components upon workpieces
IPC: H05K13/04
Filed: 1956-11-07
Abstract: 839,963. Assembling thermionic valve holders on circuit boards. BRITISH UNITED SHOE MACHINERY CO. Ltd. Nov. 7, 1956 [Nov. 8, 1955], No. 33950/56. Addition to 802,658. Class 83 (2). [Also in Group XXX] A machine for assembling electrical components on circuit boards comprises an assembling device arranged to move towards and away from a board and to releasably support a component in fixed relation thereto and means for rotating the assembling device in order to present the components in correct uniform orientation relatively to the boards. The machine is intended more particularly for the assembly of sockets for thermionic valves. The assembling device comprises a tubular rotary spindle 44 having in its lower portion a tubular stem 50 carrying a socket holder 46 with prongs 48. A spring 52 urges the holder downwards but movement of the stem 50 within the spindle 44 is limited by blocks 56 moving within slots 54. The spindle is raised and lowered by a lever 62 with a bifurcated end and rotated by a motor 72 through a clutch 80 a belt 84 and pulley 82 secured to a sleeve 90 which is slotted to receive a spline 92 on the spindle. Rotation of the spindle is stopped in the correct position of orientation of the components by the engagement of the spline 92 with a key 98 fixed to a knurled member 102 adjustably held within a bracket 104. When a pallet P carrying a circuit board W has been clamped at the working station, electric control means is automatically actuated and pressure air is admitted to an air motor 124 and its piston rod 126 and a bar 130 moved up against the resistance of a return spring 128. The bar 130 is pivoted to an actuating lever 132 which is fulcrumed on a stud 136 together with the spindle operating lever 62 and a hold-down operating lever 134. The resulting anti-clockwise movement of the lever 132 compresses a return spring 138 and is transmitted to the lever 62 through an adjustable screw 148 in the rear end of the lever so that the spindle 44 descends. An adjustable screw 152 in the lever 134 is adapted to be engaged by the lever 62 and operates a hold-down 154 with a rubber tip 155. In the base of the frame 20 is an anvil holder 162 arranged to move up in timed relation to the installing movement of the spindle 44 and to this end is coupled to the piston rod 126 by links 164, 168, 172 and a toggle 174, 176. Full and correct insertion of a socket in the circuit board depresses a plunger 184 in the anvil to operate a microswitch causing retraction of both spindle 44 and anvil. When a socket has been fully installed, the hold-down operating lever 134 is kept in lowered position by a latching lever 196, Fig. 8, so that as the rod descends the front of lever 132 engages a screw 150 to move the lever 62 clockwise to lift the spindle 44 and holder 46 while the holddown remains stationary until the lever 196 is unlatched bv a cam 202 on the lever 62. Lever 134 is then rotated quickly clockwise by a pair of springs 204 to lift the hold-down from the socket and through screw 152 to impart continued rotation to the lever 62 until finally a block 216 at the rear end of the lever 132 engages a latch 212 on a lever 214 mounted on lever 132 and connected at its lower end to the plunger of a solenoid 222. With levers 62, 132 and 134 thus latched, their continued movement by the piston of the air motor lifts the spindle 44 out of engagement with the orientating key 98 so that it resumes rotation. In addition a spring 236 is loaded due to a rod 232 being depressed by the lever 134 and also the lever 62 actuates a microswitch 248 (not shown). Sockets 42 are supplied successively from a vibratory hopper 114 to a raceway 110 down which they pass to a socket support comprising a pair of gates 26a, Fig. 6, each comprising a semi-circular recessed seat 262 and an upright arcuate stop surface 264. The gates are carried by arms 272, 278 integral respectively with a sleeve 276 and a pin 282 to which are clamped arms 284 and 290 connected by links 286 and 292 to an equalizing lever 288. Lever 288 is shifted to swing the gates in time relation to the heightwise movement of the spindle 44 by a plunger 298 under the control of a valve operated by the micro-switch 248. Springs 306 normally hold the gates open. The arm 290 is coupled by a rod 318 and bell crank lever 322 to a rotatable pin 324 carrying a wire detent 336 associated with the raceway 110 so that when the gates close, a socket is released down the raceway and is accelerated by a jet of air from a nozzle 310 on to the seats 262. As the plunger 298 moves forward a finger 342 allows a spring 344 to shift a control lever 346 beneath a ring 60 formed on the holder 46. After the actuation of a time-delay switch 256 due to an arm 252 moving away from a button 254, a solenoid 222 unlatches the lever 214 thus allowing the spring 236 to urge the hold-down 154 on to the socket seated on the gates. The lever 62 then moves to lower the spindle so that the holder 46 engages the top of the socket which is restrained from rotation by the hold-down. When the prongs 48 come into alignment with the apertures of the socket, the spring 52 acts to thrust them partly in and the ring 60 depresses the lever 346 to actuate another switch to deenergize the clutch coil and so stop the rotation of the spindle and also energizes a solenoid 354 to give a clockwise impulse to the lever 240 and strikes and impels lever 62 counterclockwise. The gates 260 are opened and the socket and holder descend and the lever 346 is pushed back to release the ring 60 and the switch 352 so that the spindle is again rotated until the spline 92 engages the key 98. Then, as soon as a pallet P is clamped in position, the socket is inserted in the board carried thereby. The electrical controlling means of the conveyer apparatus is similar to that described in Specification 819,969. Specification 802,659 also is referred to.